Process to make diels-alder modified olefin terpolymers and products therefrom

ABSTRACT

NOVEL POLYMERS ARE DISCLOSED WHICH COMPRISE MODIFIED OLEFINS CONTAINING IN THEIR MOLECULE AN ENDOMETHYLENE RING OR A CYCLOALIPHATIC RING, A STRAIGHT HYDROCARBON CHAIN AND CHARACTERISTIS POLAR GROUPS INCLUDING COOH, CN, CHO, CONH2, SO3H, CH2,CI AND COOR* WHERE R* MAY BE AN ALKYL OR AN ARYL RADICAL. THE NEW OLEFIN POLYMERS ARE OBTAINED BY A DIELS-ALDER REACTION BETWEEN OLEFIN POLYMERS CONTAINING CONJUGATED DOUBLE BONDS WITH DIENOPHYL REAGENTS HAVING AT LEAST ONE OF THE ABOVE-MENTIONED CHARACTERISTIC FUNCTIONAL GROUPS AND TO THE MIXES OBTAINED THEREBY WHICH CAN BE CROSS-LINKED WITHOUT SULFUR.

United States Patent 3,803,092 PROCESS TO MAKE DIELS-ALDER MODIFIED OLEFIN TERPOLYMERS AND PRODUCTS THEREFROM Sebastiano Cesca, San Donato Milanese, and Sergio Arrighetti, Milan, and Arnaldo Roggero and Giuseppe Ghetti, San Donato Milanese, Italy, assignors to Snam Progetti S.p.A., Milan, Italy No Drawing. Filed Apr. 16, 1971, Ser. No. 134,822 Claims priority, application Italy, Apr. 16, 1970, 23,389/70; Sept. 3, 1970, 29,294/70 Int. Cl. C08f 27/00, 15/40 US. Cl. 260-66 13 Claims ABSTRACT OF THE DISCLOSURE The present invention refers to new polymers, to the process for obtaining same and to mixes curable without sulphur which contain said polymers, More particularly, it refers to new olefine polymers obtained by reacting olefine polymers containing conjugated double bonds with dienophyl reagents having characteristic functional groups and to the mixes obtained thereby which can be crosslinked without sulphur.

It is known that all the usual elastomers, containing some unsaturations and vulcanized by sulphur and accelerators containing recipes, may cause a more rapid aging of the final products with the following degrading of the properties of the macromolecule. Moreover, the presence of disulphuric or polysulphuric bridges causes the splitting of the side chains with following internal rearrangements of the molecules and then alterations of the physical and physical-chemical characteristics.

It has now surprisingly found a new class of olefine polymers which may give rise to without sulphur curable mixes so that products can be obtained having an improved resistance to the aging agents and a more stable molecular composition.

The modified olefine polymers, which are an object of action between olefine polymers having conjugated double bonds and dienophyl reagents introducing into the macromolecule characteristic functional polar groups, generally absent in the starting polyolefine chains.

More particularly, the process of the present invention refers to olefine polymers containing in their polymer chain one of the following groups:

3,803,092 Patented Apr. 9, 1974 in which R and R are substituents different between themselves, one of them always being hydrogen and the other one being an alkadienyl radical as or alkenyl as R! RI! wherein the double bond is conjugated with a double bond present in the cycle, R always being an alkyl radical and R, R" and R' being hydrogen, alkyl or aryl radicals; or it may have the general formula: a

n ranging between 0 and 5 and Z being a cyclodiene radical selected from the following ones:

wherein R, R", R'" and R being hydrogen, alkyl or aryl radicals.

Moreover, it is possible to utilize the olefine polymers having one of the following groups in their polymer chain:

and 108,974, respectively; and in some other ones, based on the following termonomers:

Dehydrodicyclopentadieue.

I 2-pro en l-norbor-2 S-dieue. CH=HCH: p y

wherein X, X", X' and X" may be selected among H, COOH, -COOR, CN, CHO, CONH SO H, CH Cl, R being an alkyl or an aryl radical, with the provision that they all cannot contemporaneously be hydrogen and, in the case of the carbon-carbon double bond, the cis-substituents may be divalent radicals able to interact in order to form a ring.

Unrestrictive examples of the usable dienophyl reagents are the following ones:

The polar groups which have to be introduced into the starting macromolecules give the dienophyl reagents, carrying these groups, a strong reactivity, so that it is possible to work at very mild reaction conditions.

According to the process of the present invention,'the reaction is Carried out at a temperature ranging from 0 4 to 150 C., preferably from 15 to C., in hydrocarbon solutions of the olefine polymer, wherein the olefin polymer is present in the range from 0.1 to 5% on a basis of grams of polymer to cm. of the hydrocarbon solution, the percentage of this latter ranging between 0.1 and 5% The reaction times depend from the dienophyl reactivity and from the employed temperature, however, they range between 2 and 50 hours. The mixes obtained by starting from the aforesaid olefine polymers, and constituting a second object of the present invention, are vulcanized by using the usual curing agents which do not contain any sulphur.

The so obtained product, as the starting modified olefine polymer, may be largely employed in the synthetic rubber field, which they point out the technical properties of, by given them new possibilities of reaction and improved capacities of adhesion and interaction, so that giving rise to manufactured articles having very good properties as a high mechanical resistance, a high resistance to abrasion and a decrease of the permanent set.

v The invention is now illustrated by the following unrestrictive examples.

EXAMPLE 1 11 g. of a terpolyrner containing ethylene (55% by weight), propylene (42% dehydro-iso-dicyclopentadiene (3%) and having a toluenic intrinsic viscosity equal to 3.35 dL/g. at 30 C., obtained according to the Italian Pat. No. 843,706, U.S. Pat. No. 3,652,514, of the same applicant, were dissolved into 1.5 l. of toluene; 5 g. of maleic anhydride were added to it. The solution was stirred at room temperature for 8 hours, and then the polymer was coagulated by pouring the mixture into an excess of a methyl alcohol-acetone mixture (1:1). The polymer was purified again and again dissolving and coagulating it from n-hexane (four times), then dried under vacuum by heating at 50 C. The weight of the obtained product, having the aspect of uncured rubber, showed a quantitative yield with respect to the starting polymer. It had an intrinsic viscosity slightly diiferent from the ones of the starting polymer (2.26 dL/g.) and, at UN. examination, it is possible to note the total disappearance of the absorption at 236 m attributable to the system of the conjugated double bonds of the dehydroiso-dicyclopentadiene. At the same time the LR. spectrum of the modified terpolymer showed very strong absorptions, typical of the --C0O-CO group, at 1785 cm? (very strong) and at 1864 GEL-1.

EXAMPLE 2 The aforesaid example was repeated by employing 20 g. of a terpolymer containing ethylene (55%), propylene (40%), dehydro-iso-dicyclopentadiene (5%) and having {n]-=1.9 dl./g.; it was dissolved into 2 l. of toluene and added of 10 g. of maleic anhydride. The reaction suspension was stirred for 6 hours at 50 C.; then the polymer was recovered as aforesaid.

Also now the modified polymer did not show changes of the intrinsic viscosity, whereas the spectroscopic examination showed the total disappearance of the absorption at 236 m and the rise up of a strong band at 1785 cm.- and of another light one at 1864 cm.-

EXAMPLE 3 12. g. of a terpolymer containing ethylene (60%), propylene (34%) and methylcyclopentadienyl norbornenyl-methane (6%), obtained according to the Italian Pat. No. 851,691, which is US. Pat. No. 3,657,204, and having ]-=2.l dl./g., were dissolved into 700 cm. of n-heptane, to which 15 cm. of acrylonitrile were added. The solution was stirred for 24 hours at room temperature, then the modified polymer was recovered by employing the procedure of Example 1. In such a way a polymer was obtained having an elastomer aspect and [1;]-=2.7 dl./'g.; at U.V. examination it still showed an absorption at 252 my, attributable to the system of conjugated double bonds of the starting terpolymer. By referring the intensity of the registered band of the modified polymer to the intensity of the same band of the starting polymer, at the same dilution, 40% of the conjugated system of the methyl-cyclopentadienyl-norbornenyl-methane were calculated to be reacted with the employed dienophyl. The IR. spectrum of a CS film of the modified polymer showed the presence of a band at 2230 c-mr due to the stretching of the C-=N bond.

EXAMPLE 4 The preceding example was repeated by employing the same terpolymer, having a methylcyclopentadienyl-norbornenyl-methane content equal to 45% b.w.; it was dissolved into 700 cm. of n-heptane with 15 cm. of acrolein. After 24 hours of reaction at room temperature, the modified polymer was coagulated and again dissolved according to the procedure of Example 1. After drying,

an elastomer was obtained having the same molecular weight (MW) of the starting polymer, but the U.V. absorption at 252 m was very strongly lowered. It was calculated, as said in Example 3, that 83% of the termonomer had reacted 'by its system of conjugated double 5 bonds. The LR. spectrum of a sample of the modified polymer showed a very strong 'band at 1720 cm. (9 C=C) attributable to the carbonyl group of the reacted dienophyl.

EXAMPLE 5 No. 108,974, of the same applicant and having [1,] =1.6

dl./ g. A Diels-Alder reaction between it and methyl-vinyl ketone was carried out in toluene (1.5 l. for 11 g. of

6 of the starting polymer. At the same time the LR. spectrum of the recovered product showed the presence of a strong band at 1667 cmr in the typical range of the conjugated carbonyl groups.

EXAMPLE 7 11 g. of the terpolymer of Example 4 were dissolved into 1.5 l. of toluene and added with 10 cm. of ethylpropiolate in order to carry out a Diels-Alder reaction between the diene system of the macromolecules and the acetylene dienophyl.

After 8 hours of reaction at 60 C. a modified polymer was recovered showing, at U.V. examination, the disappearance of the absorption at 232 my, awardable to the system of conjugated double bonds of the starting terpolymers, whereas the LR. examination pointed out the presence of ester groups at 1712 cm. typical bond of the absorption of the unsaturated ester.

EXAMPLE 8 The preceding example was repeated by employing as dienophyl (in excess) the commercial product Celogen- AZ (azodicarboxyamide). The reaction was carried out at 90 C. in toluene for 24 hours.

EXAMPLE 9 The ethylene-propylene-dehydrodicyclopentadiene terpolymer, containing a triene percentage of 3%, obtained according to the Italian patent application No. 843,706, US. Pat. No. 3,652,514, and modified as above said by adding maleic anhydride, was used for preparing in an opened mixer four mixes having the recipe of Table I, and then was cured at 153 C. in a press at varying times.

The properties at traction of the cured products, reported on Table H, were obtained at Inston dynamometer, at a traction rate of 200 mm./min., according to the ASTM rules D-417 and by employing the Din C hollow punch.

polymers) at 50 C. for '6 hours. According to Example 1, TABLE I an elastomer was recovered showing [1 =1.75 dl./ g. and, 40 I II III IV at U.V. examination, the nearly total disappearance and Polymer 100 of the absorption at 227 m typical of the conjugated difg 5 methylene system of the employed terpolymer. Zn diethyldithioearbamate. 0.5

At I.R. examination a strong absorption of 1718 emf NaOH Esamethylenetetramme. 1 resulted, it being typical of the carbonyl group of satu- Ethyl glycol 5 rated ketones.

TABLE II I II III IV Properties 180 min. 30 min. 90 min. 180 min. 30 min. 90 min. 180 min. 30 min. 90 min. 180 min.

M 100% (kg/cm?) 13.5 24.5 25.5 29.5 23.0 25.0 25.0 27.0 32.0 33.5 M 200% k c111 15.5 49.0 53.5 53.0 45.0 49.5 48.0 33.5 50.5 55.0 M 300% (kgJcm 15.5 75.0 83.0 69.5 75.5 75.5 05.0 75. 0 c R. (kg./c 15 96 5 28.5 84.0 88.0 82.0 93.0 43.0 57.0 75.5 A R. percent 270 415 375 275 390 345 410 230 330 325 Perm. set. percent--- 7 13 13 8 11 13 13 13 13 13 EXAMPLE 5 EXAMPLE 10 Use was made of a terpolymer consisting of ethylene, propylene and 11% b.w. of 2-(2',4'-dimethyl-penta-l,3-

The ethylene-propylene-dehydrodicyclopentadiene terpolymer, with a triene content equal to 5.3% and dienyl)-norbor-5-ene and obtained according to the Italian [9 =2.26 dl./g., obtained according to the Italian Pat.

patent application No. 19,653 A/ 70, which is US. applic. Ser. No. 109,033, of the same applicant, in order to carry out a Diels-Alder condensation with t-butyl-quinone. The reaction was carried out in toluene at C. for 15 hours. The recovered polymer still had an elastomer character and showed, at U.V. examination, the total disappearance of the absorption at 234 my. typical of the termonomer No. 843,706, US. Pat. No. 3,652,514, and modified as aforesaid by adding maleic anhydride, was utilized in order to prepare in an opened mixer four mixes having the recipe of Table I; the vulcanization was carried out in a press at 153 C., at varying times.

The properties at traction of the cured product are reported on Table H.

TABLE III I II III IV Properties 180 min. 30 min. min. 180 min. 30 min. 90 min. 180 min. 30 min. 90 min. 180 min.

M (kgJcmJ) 17. 5 32. 6 28. 0 41. 0 38. 0 40. 5 44. 0 17. 5 25. 5 23. 0 M 200% (kg/emf).-. 23. O 68. 0 90. 0 100. 0 73. 5 37. 5 89. 0 31. 0 44. 3 49. 0 M 300% (kg/0111. 99. 0 109. 0 134. 0 44. 5 63. 5 81. 5 C.R. (kg/0111. 23 0 104.0 128. 0 132. 0 118. 0 140. 0 137. 0 46.0 68.0 93. 0 A.R. percent 240 335 2 335 335 285 330 335 343 Perm. set. pereen 17 8 4 4 6 5 4 13 8 8 7 8 EXAMPLE 11 (3) /R' The ethylene-propylene(methylcyclopentadienyl-norbornenylmethane), with a triene content equal to 4% R and an intrinsic viscosity l.59 dl./g., obtained ac- 5 cording to the Italian Pat. No. 851,691, which is US. Pat. No. 3,657,204, and modified by an adding of maleic an- R" hydride, was utilized to prepare in an opened mixer four (4) mixes having the recipes of Table I, which were cured in press at 153 C. at varying times, and then tractionated H at the Instram dinanometer with a traction rate equal R to 200 mm./min.

The results of the traction test are reported on Table C IV. Rir

TABLE IV I II III IV Properties min. 90 min. 180 min. 30min. 90 min. 180111.111. 30 min. 90 min. 180 min. 30 min. 90min. 180 min.

M 100% (kgjcmfi) 15.5 10.5 19.0 32.0 35.0 45.0 30.0 30.5 43.5 20.0 21.0 23.0 M (kg/cm!) 21.0 24.0 20.0 50.0 75.0 107.0 107.5 122.0 141.0 37.0 42.0 52.5 M 000% (kg/cum)- 22.5 110.0 173.0 00.0 72.0 00.0 0.1 (kg/cm!) 23.0 220 27.0 59.5 130.0 170.0 133.5 134 103.0 70.5 92.5 130.0 11.12. percent 310 220 225 335 300 235 255 M0 415 395 335 Perm. set. percent 45 10 14 0 13 s 3 0 4 27 23 17 EXAMPLE 12 in which R; and R are substitutents difierent between Some tests of adhesion on sheet-aluminum were carried themselves one of them always bemg hydrogen and on the series of the hereinafter reported polymers. the othe? selectefi from The used polymers are: a terpolymer (A) consisting of 30 (a) alkadlenyl radicals according to the formulas ethylene-propylene-dehydrodicyclopentadiene with a tri- R ene content of 3% and =3.2 dL/g. obtained according to the Italian Pat. No. 843,706, US. Pat. No. 3,652,- 514; a terpolymcr (B) equal to A but modified by maleic anhydride as aforesaid; a terpolymer (C) consisting of and ethylene-propylene-dehydrodicyclopentadiene with a triene content of 5.3% e[1 ]=2.26 dL/g. and modified as aforesaid; a terpolymer (D) consisting of ethylene-propylenemethylcyclopentadienylnorbornenylmethane was a trient R R' content equal to 4% a[fl]=1.2 dl./g., obtained according 40 to the Italian Pat. No. 851,691; a terpolymer as the pre- (b) an alkenyl radlcal of the formula ceding one but modified by maleic anhydride. R R" The polymers were pressed at 145 C. for 20 minutes, I in press with a 60 kgjcm. pressure, between two aluminum 511% having an thickflfiss; the average wherein the double bond of the alkenyl radical is conload necessary to separate the sheets was calculated by jugated with a double bond present in the ring, and means of an Instram dinamometer at a traction rate of (c) a radical of the formula mm./min.

The break away average load are reported on Table V. -(CH )n-Z TABLE v [Polymer adhesion test-metal (on aluminium sheets- 0., 20 min. in press-pressure-GO kg.lcm.*)]

A B o D EBN (DHDCP) (DHDCP+AM) (DHDCP-l-AM) (DA30+AM) (13.030) EPSYN 55 R N269 RN 229 RN 307 EN 334 RN 300 Breakaway load (kg/em.) 0.483 0.550 1.00 0.00 0.15

What we claim is:

1. The Diels-Alder modified olefine polymer produced by reacting in a hydrocarbon solution and at a temperature ranging between 0 and C.;

(A) an olefine terpolymer consisting of ethylene, propylene and a compound having conjugated double bonds according to one of the following general formulas:

in which n is a number ranging between 0 and 5 and Z is a cyclodiene radical selected from the following and wherein in all the above formulas R is an alkyl radical and R, R", R'" and R may be hydrogen, alkyl or aryl radicals, or may be divalent radicals able to give 5 ,rise to a condensed ring; with 9 (B) a dienophyl reagent selected from the group consisting of XI XII,

in which X, X", X and X are selected from H, COOH, COOR, CN, CHO, CONH SO H, and CH CI, R being an alkyl or an aryl radical, with the provisions that they all cannot contemporaneously be hydrogen and, in the case of the carbon-carbon double 'bond, the cis-snbstituents may be divalent radicals, able to interact in order to form a ring.

2. The modified olefine polymer according to claim 1 wherein the reaction is carried out at a temperature ranging between15 and 90 C.

3. The modified olefine polymer according to claim 1 wherein the hydrocarbon solvent is selected from the group consisting of toluene and n-heptane.

4. The modified olefine polymer according to claim 1 wherein the reaction is carried out in a hydrocarbon solution wherein the olefine polymer is present in the range from 0.1 to 5% on a basis of grams of polymer to cm. of the hydrocarbon solution.

5. The Diels-Alder modified olefine polymer produced by reacting in a hydrocarbon solution at a temperature ranging between and 150 C., an olefine terpolymer containing ethylene, propylene and a termonomer selected from the group consisting of dehydro-isodicyclopentadiene, methylcyclopentadienyl-norbornenylmethane, 2,3- dimethyIene-nOrbor-S-ene, 2-(2',4-dimethyl-penta-1', '-dienyl) norbor-S-ene, 2-propenyl-norbor-2,S-diene, (2-norborn--enyl)-4' or 5'-(2' or 3-methyl)-cyclopentadienylmethane with a dienophyl selected from the group consisting of maleic anhydride, acrylonitrile, acrolein, methyl-vinyl ketone, t-butyl-quinone, ethyl-propiolate and 2120- dicarboxyamide.

6. The Diels-Alder modified olefine polymer according to claim 5 wherein said termonomer is dehydro-isodicyclopentadiene and said dienophyl is maleic anhydride.

7. The Diels-Alder modified olefine polymer according to claim 5 wherein said termonomer is methylcyclopentadienyl-norbornenyl-methane and said dienophyl is acrylonitrile.

8. The Diels-Alder modified olefine polymer according to claim 5 wherein said termonomer is methylcyclopentadienyl-norbornenyl-methane and said dienophyl is acrolein.

9. The Diels-Alder modified olefine polymer according to claim 5 wherein said termonomer is 2,3-dimethylenenorbor-S-ene and said dienophyl is methyl-vinyl ketone.

10. The Diels-Alder modified olefine polymer according to claim 5 wherein said termonomer is 2-('2',4'- dimethyl-penta-1',3'-dienyl)-norbor-5ene and said dienophyl is t-butyl-quinone.

11. The Diels-Alder modified olefine polymer according to claim 5 wherein said termonomer is methylcyclopentadienyl-norbornenyl-methane and said dienophyl is ethyl-propiolate.

12. The Diels-Alder modified olefine polymer according to claim 5 wherein said termonomer is methylcyclopentadienyl-norbornenyl-methane and said dienophyl is azodicarboxyamide.

13. A cured olefine polymer, comprising the product as defined in claim 5 further cured in a press without sulphur curing agents.

References Cited UNITED STATES PATENTS 3,271,477 9/ 1966 Kresge 260877 3,408,424 10/1968 Barkhuif 260878 3,418,299 12/1968 Benedikter et al. 260!85.3 3,444,149 5/1969 Kelly 260-8078 3,448,174 6/1969 Loveless et a1 260-878 3,483,273 12/1969 Prugnall et a1 260878 3,524,826 8/1970 Kresge et al. 260-5 3,534,005 10/ 1970 Nudenberg et al. 260-79 OTHER REFERENCES Fieser & Fieser, Advanced Organic Chemistry, pp. 206-210 (1961).

STANFORD M. LEVIN, Primary Examiner US. Cl. X.R.

260--7'3 R, 78.5 R, 79.5 NV, 80.7, 80.78

53 33 UNITED STATES PATENT OFFICE CERTEFECATE OF CORRECTEON Patent No. 3,803,092 Dated April 7, 1976' Inventor) Sebastiano Cesca, Sergio Arrighetti,

Arnaldo Roggero and Giuseppe Ghetti It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

. I Column 1, between lines 51 and 52, insert the present invention, are obtained by a Diels-Alder re- Column 3, line 40, "he" should read the Column 4, line 36, "purified again" should read purified by again Column 5, line 38, "50 C." should read 50C.

Column 6, line 13, "awardable" should read attributable Column 6, line 34, "Inston" should read Instron Column 7, line 11, "Instram" should read Instron "dinanometer" should read dinamometer Column 7, line 39, was a trient should read with a triene Column 7, line +7, "Instram" should read Instron Column 9, line 35, "3methyl" should read 3' -methyl Signed and sealed this 5th day of November 1974.

(SEAL) Attest:

MCCOY GIBSON JR. C. MARSHALL DANN Attestlng Officer Commissioner of Patents 

